February 2012, Volume 8, Issue 2
Published by AEGIS Communications
Posterior Restorations Using a Nanohybrid Composite
For use in both the anterior and posterior, this universal nanohybrid composite enables the creation of wear-resistant, esthetic, durable, and easily polishable restorations.
By Douglas L. Lambert, DDS
Conventional direct composites have presented dentists with limitations, such as suitability for either the anterior or posterior regions—but not both—based on their material, physical/strength, and optical/esthetic properties. Some generations of composites were suitable for the anterior because they polished well and demonstrated exceptional esthetic characteristics but lacked strength and durability. Other composites were suitable for the posterior based on their wear and strength characteristics, but their esthetic qualities precluded their use in the esthetic zone. Further, successfully filling a posterior cavity preparation often required alternating placement and curing of multiple layers of composite to ensure complete polymerization, reduce the likelihood of shrinkage stress, and prevent postoperative sensitivity and restorative failures.
Today, however, universal nanohybrid composites (such as Tetric EvoCeram®, Ivoclar Vivadent®, www. ivoclarviva
dent.com) are available for use in creating wear-resistant and esthetic, durable, and easily polishable direct restorations. For efficient placement, Tetric EvoCeram demonstrates an ideal consistency that can be placed simply and efficiently using either syringes or Cavifils (Ivoclar Vivadent). Tetric EvoCeram is highly radiopaque, clearly visible on radiographs, and distinguishable from changes in the dental hard tissues, such as secondary caries. As a true universal nanohybrid composite, it is indicated for use in both the anterior and posterior.
Of significance, when sculpting and contouring restorations—particularly those associated with Class II preparations—Tetric EvoCeram features an on-demand polymerization system, which enables dentists to fully contour restorations and control the polymerization process of the material itself. Because Tetric EvoCeram is less reactive to ambient light than other materials due to its patented additive into the photoinitiator system, it provides excellent working and setting times, yet it also demonstrates high reactivity to curing lights within the wavelength range of 400 nm to 500 nm, ensuring a complete depth of cure.
Tetric EvoCeram is formulated with monomers and nano-color pigments, which work together in its filler particles to create a unique refractive index that allows restorations to blend with natural tooth structures. Additionally, shade adaptation is enhanced by the material’s high translucency, which facilitates the shade-matching process in cases requiring direct restorations.
Further contributing to Tetric EvoCeram’s natural-looking characteristics is the average size of the nanohybrid filler particles, which is less than 550 nm. The composite is easily polished in 30 seconds, demonstrating a high level of gloss comparable to pure microfilled and nanofilled materials. To further enhance esthetic outcomes, Tetric EvoCeram is available in a broad range of shades.
A patient presented with occlusal and distal caries on tooth No. 4 that were noted radiographically (Figure 1). After a thorough examination and consultation with the patient, it was agreed that a direct composite restoration using a nanohybrid composite (Tetric EvoCeram) would be the most conservative treatment option.
A conservative slot preparation was created and caries removed (Figure 2). A fine diamond was used to bevel the enamel cavosurface margins (Figure 3). The Class II preparation was isolated using a sectional matrix, Wave-Wedge (Triodent, www.triodent.com), and V-3 Ring (Triodent) to create a sealed system (Figure 4).
A self-etch adhesive (AdheSE®, Ivoclar Vivadent) was applied to all enamel and dentin preparation surfaces (Figure 5). A small increment of flowable composite (Tetric EvoFlow) in shade A1 was syringed into the proximal box (Figure 6). However, this layer was not cured at this time.
The body composite (Tetric EvoCeram) in shade A1 was syringed on top of the uncured flowable composite, filling the entire preparation in a 4-mm increment (Figure 7). The hydraulic action of the body composite allowed the flowable composite to assist in sealing the Class II cavosurface margins. The uncured Tetric EvoCeram composite was condensed with a P-1 Plugger (Ivoclar Vivadent) lubricated with an unfilled resin (Heliobond, Ivoclar Vivadent) to create occlusal anatomy prior to curing (Figure 8).
Upon completion of contouring, the restoration was cured with light-emitting diode (LED) curing lights for 20 seconds through both the buccal and lingual cusps (Figure 9). The V-3 Ring was removed and the sectional matrix was peeled back to allow additional light-curing for 20 seconds from both the buccal and lingual aspects (Figure 10). The Wave Wedge and sectional matrix were removed, revealing a tight proximal contact with excellent contours created by the V-3 system, which helped to minimize finishing time (Figure 11).
The restoration was contoured and shaped using 12-fluted, spiral-bladed carbides (Figure 12 and Figure 13). Occlusal and excursive contacts were checked with articulating paper in both reclined and vertical seating positions (Figure 14). Finally, the restoration was polished with abrasive points and cups (Astropol, Ivoclar Vivadent) (Figure 15 and Figure 16).
The simplicity with which esthetic and predictable posterior Class II restorations can be completed is beneficial to both dentists and their patients (Figure 17). The handling and material properties demonstrated by Tetric EvoCeram facilitated easy placement, contouring, and polishing of the posterior restoration featured in this article. Additionally, the material’s optical properties contributed to an esthetic and “invisible” posterior restoration that is indistinguishable from the surrounding natural dentition. For Class II restorations, Tetric EvoCeram demonstrates the easy adaptability and ideal working time required, enabling fillings to be completed predictably and efficiently.
About the Author
Douglas L. Lambert, DDS